gui: Make some functions return void.
[paraslash.git] / bitstream.c
1 /*
2 * Common bit I/O utils.
3 *
4 * Extracted 2009 from mplayer 2009-02-10 libavcodec/bitstream.c.
5 *
6 * Copyright (c) 2000, 2001 Fabrice Bellard
7 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
8 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
9 *
10 * Licensed under the GNU Lesser General Public License.
11 * For licencing details see COPYING.LIB.
12 */
13
14 /**
15 * \file bitstream.c Bitstream API.
16 */
17
18 #include <stdlib.h>
19 #include <inttypes.h>
20 #include <stdio.h>
21 #include <string.h>
22 #include <regex.h>
23
24 #include "para.h"
25 #include "error.h"
26 #include "string.h"
27 #include "wma.h"
28 #include "bitstream.h"
29
30 #define GET_DATA(v, table, i, size) \
31 {\
32 const uint8_t *ptr = (const uint8_t *)table + i * size; \
33 switch (size) { \
34 case 1: \
35 v = *(const uint8_t *)ptr; \
36 break; \
37 case 2: \
38 v = *(const uint16_t *)ptr; \
39 break; \
40 default: \
41 v = *(const uint32_t *)ptr; \
42 break; \
43 } \
44 }
45
46 static void alloc_table(struct vlc *vlc, int size)
47 {
48 vlc->table_size += size;
49 if (vlc->table_size > vlc->table_allocated) {
50 vlc->table_allocated += (1 << vlc->bits);
51 vlc->table = para_realloc(vlc->table,
52 sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
53 }
54 }
55
56 static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
57 const void *bits, const void *codes, int codes_size,
58 uint32_t code_prefix, int n_prefix)
59 {
60 int i, j, k, n, table_size, table_index, nb, n1, idx, code_prefix2,
61 symbol;
62 uint32_t code;
63 VLC_TYPE(*table)[2];
64
65 table_size = 1 << table_nb_bits;
66 table_index = vlc->table_size;
67 alloc_table(vlc, table_size);
68 table = &vlc->table[table_index];
69
70 for (i = 0; i < table_size; i++) {
71 table[i][1] = 0; //bits
72 table[i][0] = -1; //codes
73 }
74
75 /* map codes and compute auxillary table sizes */
76 for (i = 0; i < nb_codes; i++) {
77 GET_DATA(n, bits, i, 1);
78 GET_DATA(code, codes, i, codes_size);
79 /* we accept tables with holes */
80 if (n <= 0)
81 continue;
82 symbol = i;
83 /* if code matches the prefix, it is in the table */
84 n -= n_prefix;
85 code_prefix2 = code >> n;
86 if (n <= 0 || code_prefix2 != code_prefix)
87 continue;
88 if (n <= table_nb_bits) {
89 /* no need to add another table */
90 j = (code << (table_nb_bits - n)) & (table_size - 1);
91 nb = 1 << (table_nb_bits - n);
92 for (k = 0; k < nb; k++) {
93 if (table[j][1] /* bits */ != 0) {
94 PARA_EMERG_LOG("incorrect code\n");
95 exit(EXIT_FAILURE);
96 }
97 table[j][1] = n; //bits
98 table[j][0] = symbol;
99 j++;
100 }
101 } else {
102 n -= table_nb_bits;
103 j = (code >> n) & ((1 << table_nb_bits) - 1);
104 /* compute table size */
105 n1 = -table[j][1]; //bits
106 if (n > n1)
107 n1 = n;
108 table[j][1] = -n1; //bits
109 }
110 }
111
112 /* fill auxillary tables recursively */
113 for (i = 0; i < table_size; i++) {
114 n = table[i][1]; //bits
115 if (n < 0) {
116 n = -n;
117 if (n > table_nb_bits) {
118 n = table_nb_bits;
119 table[i][1] = -n; //bits
120 }
121 idx = build_table(vlc, n, nb_codes, bits, codes,
122 codes_size, (code_prefix << table_nb_bits) | i,
123 n_prefix + table_nb_bits);
124 /* vlc->table might have changed */
125 table = &vlc->table[table_index];
126 table[i][0] = idx; //code
127 }
128 }
129 return table_index;
130 }
131
132 /**
133 * Build VLC decoding tables suitable for use with get_vlc().
134 *
135 * \param vlc The structure to be initialized.
136 *
137 * \param nb_bits Set the decoding table size (2^nb_bits) entries. The bigger
138 * it is, the faster is the decoding. But it should not be too big to save
139 * memory and L1 cache. '9' is a good compromise.
140 *
141 * \param nb_codes Number of vlcs codes.
142 *
143 * \param bits Table which gives the size (in bits) of each vlc code.
144 *
145 * \param codes Table which gives the bit pattern of of each vlc code.
146 *
147 * \param codes_size The number of bytes of each entry of the \a codes tables.
148 *
149 * The wrap and size parameters allow to use any memory configuration and
150 * types (byte/word/long) to store the bits and codes tables.
151 */
152 void init_vlc(struct vlc *vlc, int nb_bits, int nb_codes, const void *bits,
153 const void *codes, int codes_size)
154 {
155 PARA_INFO_LOG("nb_codes: %d\n", nb_codes);
156 vlc->bits = nb_bits;
157 vlc->table = NULL;
158 vlc->table_allocated = 0;
159 vlc->table_size = 0;
160 build_table(vlc, nb_bits, nb_codes, bits, codes, codes_size, 0, 0);
161 }
162
163 void free_vlc(struct vlc *vlc)
164 {
165 freep(&vlc->table);
166 }
167
168 /**
169 * Parse a vlc code.
170 *
171 * \param gbc The getbit context structure.
172 *
173 * \param table The vlc tables to use.
174 *
175 * \param bits The number of bits which will be read at once, must be
176 * identical to nb_bits in init_vlc().
177 *
178 * \param max_depth The number of times bits bits must be read to completely
179 * read the longest vlc code = (max_vlc_length + bits - 1) / bits.
180 *
181 * \return The vlc code.
182 */
183 int get_vlc(struct getbit_context *gbc, VLC_TYPE(*table)[2], int bits,
184 int max_depth)
185 {
186 int n, idx, nb_bits, code;
187
188 idx = show_bits(gbc, bits);
189 code = table[idx][0];
190 n = table[idx][1];
191 if (max_depth > 1 && n < 0) {
192 skip_bits(gbc, bits);
193 nb_bits = -n;
194 idx = show_bits(gbc, nb_bits) + code;
195 code = table[idx][0];
196 n = table[idx][1];
197 if (max_depth > 2 && n < 0) {
198 skip_bits(gbc, nb_bits);
199 nb_bits = -n;
200 idx = show_bits(gbc, nb_bits) + code;
201 code = table[idx][0];
202 n = table[idx][1];
203 }
204 }
205 skip_bits(gbc, n);
206 return code >= 0? code : -E_VLC;
207 }